Conventionally, in a construction using a steel pipe column, there is a case in which a beam of H shaped steel is connected. To connect the column and the beam, a through-diaphragm corresponding to the height of a flange part of the beam is provided to transmit stress from the beam to the column efficiently at a connection part thereof. The through-diaphragm is a plate-like member that is connected by welding and the like between a column and a column. Generally, the flange part of the beam is butted against the side surface of the through-diaphragm and welded.
However, there are cases in which the sizes (heights) of the beam that is connected to the column are not same in all directions. For example, there is a case in which a beam having a shorter height in one direction is connected. In such a case, it is impossible to connect at least one of the upper and lower flanges of the beam to the through-diaphragm to which another beam is connected.
To connect such a beam having different heights, a connection structure of column-and-beam wherein, a square-shaped section pipe, a cross-shaped plate that supports two parallel sides of the square-shaped section pipe, and a tilted plate that supports two sides holding a corner part of the square-shaped section pipe are integrally formed by casting; an edge part of a column-and-beam connection metal is welded to the square-shaped section pipe, the column-and-beam connection metal having peripheral surface which are flat shaped at least at the area on which the beam is attached; and an H shape beam is connected by non-scallop welding to the peripheral surface of the column-and-beam connection metal is proposed (See Patent Document 1).